As mobile communication services have been rapidly developed, and users using the mobile communication services have been exponentially increased, portable terminals have been provided with various functions. For example, the portable terminals have been realized in the form of multi-media devices having multiple functions, such as a video telephony as well as a basic voice call, wireless Internet access, electronic payment, a digital camera function to photograph a still image or a moving picture, MP3 and PMP functions to reproduce music or moving pictures, and a DMB function to receive broadcasting.
Accordingly, the portable terminal has various pieces of information including a still image, a moving picture, a text file, or a text message related to the privacy of a user, which should not be exposed to other persons. Further, the portable terminal has personal information such as an ID, a password, and a certificate for electronic payment.
Accordingly, recently, in a portable terminal such as a smart phone, security for the identify theft prevention and privacy protection for various pieces of personal information stored in the portable terminal is significantly important. As one manner to enhance the security for the portable terminal, a use restriction function by screen locking is used.
If the use restriction function by the screen locking is set in the portable terminal as described above, even if a user loses the portable terminal or is away from a place while leaving the portable terminal, since others cannot activate functions of the portable terminal due to the set use restriction or see the information stored in the portable terminal, various pieces of personal information or important documents stored in the portable terminal can be safely protected.
Representative setting and releasing manners of the use restriction for a portable terminal according to the related art will be described below.
First, a user sets a password by inputting a plurality of secrete numbers through a number inputting display part. Only when numbers matching with the setting password are input, the use of the portable terminal is allowed by releasing the use restriction. The password is generally related to the specific information of the user, such as the birthday, or the phone number of the user, so that others may easily find the password. In addition, the password is usually matched to a password of a bank account, a password for the entrance of a door, or a log-in password for the Internet. Accordingly, when the password leakage occurs, secondary damages may be caused.
Thus, as shown in FIG. 33, a method is mainly used that a portable terminal is enabled to be usable by releasing the use restriction only when a user sets a password by inputting a shape pattern according to a moving locus through a pattern input display part, and a shape pattern matched to the set password is input.
However, in all methods of setting and releasing the use restriction according to the related art, since a password is input through a touch screen provided on the front surface of a main body of a portable terminal, when the user inputs a password or a shape pattern to release the use restriction, the input screen and an inputting behavior of the user cannot help being exposed to others so that security may be vulnerable.
Especially, even when a portable terminal is not used for a while, the portable terminal is immediately in a use restriction mode according to a power saving mode, so that a user should frequently input a password to release the use restriction, Thus, whenever that the user inputs a password into the front touch screen while seeing the front touch screen, others may peep into the input screen and the inputting behavior of the user, so that there may be a great danger to expose the password for usage restriction to others.
Further, since the security is vulnerable, the user should carefully input passwords such as secret numbers or shape patterns or frequently change passwords while paying attention to whether others peep at the passwords when the user inputs the passwords with the concerns about the leakage of the passwords, and when the user frequently changes passwords, he or she may remember the changed new password, making it possible to use the portable terminal.
Meanwhile, in order to solve the danger of leakage of a password, a method of providing the portable terminal provided with a fingerprint recognition section to set or release us restrictions through recognition of a fingerprint has been suggested.
However, since a fingerprint of the user itself is encrypted in the setting/releasing method through the recognition of a fingerprint, the method has an excellent security having no concern about leakage of a password in the everyday life, but in a specific situation, for example, when the user is not clearly conscious, for example, when the user is totally drunken or slept deep or when the user is under pressure, the use restriction for the portable terminal is immediately released as long as the others bring a finger of the user into contact with the finger recognition section stealthily or compulsorily, the method is more vulnerable than the setting/releasing method through secret numbers or pattern passwords.